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aynaud’s phenomenon is a disorder charac-
terized by one or more fingers becoming
blanched, cyanotic, and red (often in that
order), upon an individual’s exposure to cold

stimuli or emotional stress.1 These color changes are
attributable to several factors; however, they mainly
result from vasospasms of the digital arteries. The disor-
der occurs fairly commonly and can have a variety of
other presentations, ranging from mild discomfort to
severe pain in the affected fingers. It can eventually lead
to ulcerations, tissue necrosis, and gangrene. This article
reviews the history behind the first description of Ray-
naud’s phenomenon and discusses classification of the
disorder. The article also reviews issues relating to the
disorder’s pathogenesis, clinical features, diagnosis, and


Maurice Raynaud (1834–1881) was a French physi-
cian who trained at the University of Paris. He received
a doctoral degree in medicine in 1862 upon complet-
ing his thesis entitled “Local Asphyxia and Symmetrical
Gangrene of the Extremities.”2 He went on to earn
another doctoral degree in letters for historical re-
search in medicine and was elected to the Academy of
Medicine in 1879.

In his thesis, Raynaud described several patients who
developed cyanosis and other discolorations of their fin-
gers when the digits were exposed to cold. One patient
was described as having cyanosis “at the [tips] of the fin-
gers” followed by the development of “a vermilion red”
discoloration, which occurred every time her hands
were exposed to the cold. Another patient had a quite
dramatic reaction, which he described as follows:

So soon as she allows her hands to be exposed to a
rather low temperature the fingers become pale,
oedematous, half flexed; they are attacked with
painful sensations, numbness, and torpor; shortly
afterwards, they become blue, then black, in their
whole extent.2

This patient, however, was suspected of having scle-
roderma by those who later reviewed Raynaud’s thesis,
because she died less than 2 years after the onset of
these and other symptoms, including atrophy of the
fingers and toes, loss of facial expression, discoloration
of the skin, and feebleness.

Raynaud believed that the pathogenesis of the phe-
nomenon was attributable to a local reflex that mediat-
ed the constriction of the digital blood vessels. He car-
ried out studies, including a pathologic examination of
the digital arteries and experiments involving the inter-
ruption of the cervical sympathetic chain, but found
that he could not elicit the phenomenon or explain its
occurrence in any way other than as a local, possibly
neurally mediated reflex. Since that time, more de-
tailed descriptions of potential mechanisms involved in
the pathogenesis of Raynaud’s phenomenon have
been outlined and are discussed later in this article.


An instance of Raynaud’s phenomenon has tradi-
tionally been classified as Raynaud’s disease when it
occurs as a primary disease of unknown cause and as
Raynaud’s syndrome when it occurs secondary to a con-
nective tissue disease, such as scleroderma.3 This


Dr. Urbano is in general internal medicine, Mount Laurel Primary Care
Physicians, Mount Laurel, NJ.

www.turner-white.com Hospital Physician September 2001 27

R e v i e w o f C l i n i c a l S i g n s

Series Editor: Frank L. Urbano, MD

Raynaud’s Phenomenon

Frank L. Urbano, MD


Characterized by pallor, cyanosis, and reddening of
the fingers (and sometimes other areas of the body).
The color changes of the skin are usually precipitated
by cold stimuli or emotional stress.

method of classification has caused some confusion
among physicians, which has led some authors to sug-
gest a clearer way of distinguishing cases of Raynaud’s
phenomenon4 by using the terms primary Raynaud’s phe-
nomenon (PRP) and secondary Raynaud’s phenomenon
(SRP). PRP is used to designate Raynaud’s phenome-
non that is primary or idiopathic in nature.4 SRP—
marked by the same pathophysiology, signs, and symp-
toms as PRP—is used to designate Raynaud’s
phenomenon resulting from some known underlying
disease, medication, or event.4

Diseases associated with SRP are numerous and in-
clude scleroderma, systemic lupus erythematosus,
rheumatoid arthritis, Sjögren’s syndrome, and many
other vasculitides.4 Other more common conditions
that have been associated with SRP include peripheral
vascular disease, diabetes mellitus, and carpal tunnel syn-
drome. Also, certain medications, such as β-blockers
and ergotamine, have been associated with SRP. Occu-
pational exposure to hand-transmitted vibration, trau-
ma, and certain chemicals may be related to SRP, as well;
in one study, approximately 38% of cases of Raynaud’s
phenomenon in men were estimated to have arisen
from exposure to hand-transmitted vibration.5 However,
this incidence was much lower in women.


The pathogenesis of Raynaud’s phenomenon is not
completely understood. However, it can potentially
involve several mechanisms that could give rise to the
vasospasms of the digital arteries.6 One mechanism cor-
responds to the increased sympathetic nervous system
activity observed in patients with Raynaud’s phenome-
non. This increased activity is probably due to an in-
creased density of α-adrenergic receptors on peripheral
blood vessels. This increased density can cause the
digital blood vessels to be hyperreactive to sympathetic
stimuli. The hyperreactivity could, in turn, lead to the
vasospastic attacks in the patients. Also, patients with Ray-
naud’s phenomenon have a central nervous system
sympathetic baroreceptor reflex abnormality. This abnor-
mality can cause exaggerated vasoconstriction of the dig-
ital blood vessels when the baroreceptors are activated.

Moreover, the vascular endothelium is thought to be
involved in the pathogenesis of Raynaud’s phenome-
non3,6; patients exhibit both endothelial damage and
dysfunction. The damage may be attributable to repeat-
ed vasospastic attacks causing ischemic reperfusion
injury to the endothelium. This injury causes the re-
lease of free radicals and other products that damage
the endothelium. Endothelial dysfunction results from
a decrease in the vasodilatory chemical nitric oxide.

The cause of this decrease is not known, but the effect is
a failure of the endothelium to appropriately relax,
which results in vasospasms.

Neurohormonal factors are also considered to be
important in the pathogenesis of Raynaud’s phenome-
non. The vasoconstrictor, endothelin-1, is abnormally
elevated in patients, and there is a decrease in the num-
ber of neurons containing calcitonin gene–related pep-
tide (CGRP), a very potent vasodilator. Some recent
research has focused on the latter of these compounds7:
researchers have observed that there is a specific deficit
of CGRP neurons in the digital skin of patients with the
disorder. This deficit undoubtedly leads to vasospasms.
CGRP neurons have been found in many organs, a fact
that may explain the systemic effects observed in some
patients with Raynaud’s phenomenon.3

Hematologic abnormalities have also been observed
in patients with Raynaud’s phenomenon and may con-
tribute to its pathogenesis. Abnormal platelet and leu-
kocyte aggregation has been observed. Elevations of the
levels of factor VIII–von Willebrand factor antigen and
fibrinogen have also been observed, with the level of
the former correlating to the severity of the vasospastic


Classically, Raynaud’s phenomenon is associated
with 3 specific stages—the so-called triphasic color
change—in response to an individual’s exposure cold
stimuli (or emotional stress).3 Initially, pallor develops
in the fingers; this is caused by vasospasm of the digital
arteries and concomitant reduction in blood flow. Next,
cyanosis develops; this is caused by pooling of deoxy-
genated blood and then flow of this deoxygenated
blood through the digital blood vessels.